Control apparatus for turbojet engines



4' Sheets-Sheet l Nov. 3, 1953 LEE u CONTROL APPARATUS FOR TURBOJET ENGINES Filed Nov. 21, 1947 ATTORNEY NN l Nov. 3, 1953 L. LEE n 2,657,530

l CONTROL APPARATUS FOR TURBOJET ENGINES Filed Nov. 21, 1947 4 sheets-sheet 2 F IG. 2

BARONIETRIC CONTROL.

INCREASING COMPRESSOR PRESSURE DIFFERENTIAL MOVE ENGINE DRIVEN WATE R VALVE SUBJECT TO TAIL. PIPE TEMPERA INVENTOR I EIGHTON EE Il;

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ATTORNEY f @p -y E TORQUE- MEASURING FLUID PRESSURE COMPRESSOR IN I .E'l'

Nov. 3, 1953 L. LEE u 2,657,530

CONTROL APPARATUS FOR TURBOJET ENGINES Filed N ov. 21, 1947 4 Sheets-Sheet 3 COMPRESSOR F IG. 3

INI-ET PRESSURE EVAC UATED COMPRESSOR 302 NL FIG 5 PRESSURE coMPRESSoR l 4V V DISCHARGE 4 PRESSURE P- clggn-.FSR

` /355 380? 373w PRESSURE PRESSURE INVENTOR I E IGHTON L EE J1 www ATTORNEY Nov. 3, 1953 L. -LEE n 2,657,530

CQNTROL' APPARATUS FOR TURBOJET ENGINES Filed Nov. 21, 1947 4 Sheets-Sheet 4 V led July 19, 1947.

Patented Nov. 3, 1953 CONTROL APPARATUS FOR TURBOJET ENGINES Leighton Lee II, Rocky Hill, Conn., assignor to Niles-Bement-Pond Company, West Hartford, Conn., a corporation of New Jersey Application November 21, 1947, Serial N o. 787,416

11 claims. l

The present invention relates to hydraulic control apparatus. It is illustrated as applied to an internal kcombustion engine of the turbine type, certain features of the invention are of utility in connection with control apparatus generally, While others are useful only in hydraulic control apparatus, and still others are useful only in connection with control systems for internal combustion engines.

The particular embodiments of my invention described herein areV intended for the control of the fuel flow, speed, and output torque of an internal combustion turbine adapted to drive an aircraft by means of ra discharge jet and a Variable pitch propeller. Y

The present invention is intended as an improvement of the apparatus shown and claimed in my copending application Serial No. 761038 In that prior application, I have shown a control system in which the fuel flow and torque load of an internal combustion engine are controlled in response tothe rate of air flow through the engine, the engine speed, the enginek temperature, and the position of' a manually movable control device.

A general object of the present invention is (Cl. Gil-39.28)

to improve and simplify the propeller pitch or Y torque control illustrated in my said prior application.

Other and more specific objects are: (1), to provide for manual control of the propeller pitch in emergencies; (2), to provide compensation for the rate of change of the engine torque to prevent hunting of the control system; and (3) to provide compensation for the operation of Water injection or other combustion modifying apparatus.- Y Y Another general object is to provide, in a control system of Ythe type described, improved response to the rate of now of air-through the engine and to the air density.

Still another general object is to provide improved hydraulic control'apparatus. Y Morespecic objects in connection with this general object are kto providerimproved emergency manual control mechanism, improved mechanism responsive to the rate ofchange of a controlling condition, and improved valve mechanism for controlling a hydraulic servomotor.

Other objects and advantages of the present invention will become apparent from a consideration of theV appended speciication, drawings, in which Figure 1 is a schematic drawing of a complete control system embodying my invention,

claims and Figure 2 is a somewhat diagrammatic illustration of a propeller torque control system Which forms a part of the system of Figure l,

Figure 3 illustrates a pressure responsive control mechanism which forms a part of the system of Figure l, and shows one form which the barometric control of Figure 2 may take.

Figures 4 and 5 illustrate modified forms of barometric controls which may be substituted for the barometric control of Figure 3,

Figure 6 illustrates la modied form of valve mechanism which may be substituted for one of the valve mechanisms of Figure 2, and

Figure '7 illustrates the fuel supply control system which forms a part of the complete system of Figure 1.

Referring to the drawings, the internal combustion turbine engine is generally indicated at It, and includes a casing I2, an air inlet I4, a multiple stage compressor I6, a series of combustion chambers I8, Va multiple stage turbine 20, and discharge pipe or tail pipe 22.

Fuel is supplied to the engine from a tank (not shown) through a conduit 24, a pump 26, and a conduit 28 leading to a fuel manifold 30, from Which a series of distributing conduits 32 lead to a number of fuel nozzles 34 located in the combustion chamber I8.

Provision is also made for supplying water, a Water-alcohol mixture, or other suitable combustion modifying' liquid to the combustion chambers I8. The Water supplying mechanism includes a tank 36, from which the waterows through a conduit 38, a pump 40, a valve 42, and a conduit I4 to a Water manifold 46, from which a number of distributor conduits 48 lead to individual water nozzles 50 in the combustion chambers I8. The valve 42 may be' provided, for the purposes of the present invention, with anyV suitable manual or automatic control. A branch conduit 52 conveys the pressure of the Water being delivered to the water nozzles to the control apparatus shown diagrammatically at 54 in Figure l and described in greater detail in Figure 2. Y Y

The fuel pump 26 is of the variable delivery type, and its delivery is controlled by the pressure conveyed to it from control apparatus 54 through a conduit 56.

Y VThe engine I Il drives, through a suitable reduction gearing, a propeller 58, whose pitch is conl ing at the inlet and outlet, respectively, of the compressor to the control apparatus 54.

A torque meter generally indicated at 88 sup plies to the control apparatus 54 a pressure which measures the torque load on the engine. This torque meter comprises a planetary gear mechanism which `I'forms parts of "'.the .freduction l gear between xthe engine and the ypropeller. "This planetary gear includes a Sun gear 10, a ring gear 12, and planet gears 14 carried by a spider 16. The sun gear 10 and theringfgear `1,2..are connected to the engine and 'to the propeller. The spider 16 has an arm 18 connected through a rod 80 to a piston 82, whichmoves:imaycylinder 84. The reaction on the zspider 21E clue tolthe v torque load of the propeller is transmittedl bythe piston 82 to suitable fluid in .thercylindersM and is communicated through the conduit 86 to the control apparatus 54.

The pilot of the aircraft is provided with an engine control lever :8 .'xed on asshaft '1190 aand :movable vwith respect .ztora control :quadrant 392. The quadrant 92 is preferabjlyzprovidediWithna scale 94, illustrated Yas :,beingfmarked :.infdegrees. The shafted is Yconnected through yal'suitable link- -fage `to `a shaft 195 `in .the controlrapparatus :54. The control apparatusz v.is =also1provided -with tanV engine driven l.shaft 196,"whichsupplies :power "to iti for Jcontrol purposes.

The torque .meteri is showndiagrammatically only vll-more1complete description 4of yanother 'typezof ftorquemeter which vmay falternatively be used is .foundlinimy .copendingwapplication .Serial ,No 16545979, iiled 4March 16,..1946,-entitled :Indicating ,-Apparatus, now Ratent rNo. 2;450,835.

Figure y2 There isf--shownfinFigure2i theftorque regulatf'ing mechanism f in 'the 4control apparatus 154. This mechanism regulates" thev torque lay-controli.ling the pitchvof the Variable pitch lpropeller driven by the engine.

'There is shown fin -Figure I2 -a shaft 462, #corresponding to :the `shaftff-SZ vof Figure l1, twhose S.angular positiondetermines the pitch :of 4'the variable pitch propeller. -'Attached vto* the-:shaft '62 is a-segmental gear |00, which Aengages araclr |02 in the side of a piston |i04. "Therpiston 5|04 is vsubj ect gto' iiuid: pressures lapplied to its-opposite ends, whichs'determinei its fposition. irIhese fpressuressarei-controlled byia value1 mechanism :generally indicated fat .1206. The :valve lmechanism `:|05 includes :a piston .valve lL08-subject :.onits `bottom lsurface-:to the torque :measuring :fluid pressurecapplied through 'cor1duitf;8|'-A tof 'af chamher fI I0. This :pressure `acts .upwardly-on :the valve |08. The pressureis .opposedby a downwardlysacting -forca-.applied -,through a .rod I |2 anda lever.mecl'ianismv I IA-,bya .spring I B. The Y force oftspring .I I6 is determinedby theV angular position. .of `a..cam 8. .Cam I |:8 iskeyedto .the manually operated .main ,control .shaft .95.

The torque control is operated primarily vin response to .the balance or unbalance between the torque measuring iiuid pressure in chamber ||0 and the force .of spring IIS. The torque control may also be modied'bya barometric control Vschematically indicated yat 120, which varies the -positionpf a `bearing- |2.2in the -lever mechanism I i4 in accordance with leither the compressorrinlet absolute .pressure (when'finthe 'form 'shown' in Figure 3) or'the. differential {between the compressor inlet anddischarge pressures (Figure `4), or =the sumofthe compressor inlet and-discharge -absolute pressures (Figure 5) all of which vary the rate of flow Aof combustion air through the compressor. Provision is also made for modifying the torque control when Water or other combustion modifying liquid is being supplied to the combustion chambers. The water pressure responsive mechanism includes a control-valve *E224 which "operatesfa uid motor -|28 lto shiftf'the'cam i'H8 7so `that it presents a different surface to its follower |28 when water *is being supplied to the engine- .Limit .controls .are also provided which vary the torque control in response to engine speed and engine temperature. The speed limit control fincludes ia governor |30 and the temperature flimitcontrolincludes a control valve mechanism generally; indicated at I 3 2.

Thewalveimechanism |06 which controls the piston |04 includes the valve |08, which has a pair'of' lands |34 and |36 separated by a recess |38. The valve mechanism is enclosed Within a rvcasing |40. 'The valve.; luxmovesfwithinfaj pair of generallya cylindrical seat members |42 :and |144. The seat :members e r4.2 and |'44:.:arezprovidedwith 'central .bores Which-eextend axiallyzthrough; hem .iromsend to end'to;receive'the'valveiIllS. @Each .ofxthese seat lmembers |42 z-and 'I44zaiso has .a l larger bore concentricawith 1 its tcentral ".borezand yextending inwardlygfromoneipof .its ends. L'Ihe seat members |42 and |44 are arrangedwithin :the `casing "|240 eso :that :these larger loores'face each other. .1A vvsleeve L46. Lis .received '.Withinthe two larger bores.

' Thersleeve; |340l is made-slightly.'longerzthanzthe combined depthof Ythe bores in-.the .seatgmembers |42 and |44, so that when theesleeve:an`d:;the1.two

*seat members cartel-assembled, @the facing end of the-.two :seat rmembers are .held lspacedpfapart .by the isleeve.V ySleeve f|4 vhas :radial ;:grooves |48 cut .in its endzfaces :fand annular .recesses i |-501at the peripheryofieachrof. its yend races. ,The-.seat Imembersl |42s-and Ie44rareprovided-:with ports Y |52 and |54-=which .connect the annular recesses |50 with :external grooves `|58 and |58, respectively, .inthefseat-members |42fand |44. Groove `|56 is connected tofafconduit `|60 which. leadsftothe .upper'send vof `the' cylinder |62 inlwhic'h'the; piston |f|ll|moves,V `andrgroove |158 isconnected `through a 3.conduit I 64 i to v. the =lower :end 'of y cylinder I B2.

An inlet for hydraulic fluid under pressure yris provided linl the .valve mechanism f 0 6 through a conduit |06 which openss intorthe space between the fseat :members f .I 42 .and I 44. The -fluid .then passes through -.onev or fmore ,radial inlet sports :|168 in; the .sleeve I 4B tothe recess |-3 Bbetween` the 'lands |:34-andfl36 onvalve |03. The landsISll and 3 6 @are providedwith .flat y:surfaces |10 and |12, which are of triangular or curved contour so `asi-to yprovide .'ports o'ftapering depth. 'These triangular for curved .iiiats have ytheir apexes pointed towards u.the 'recess 1.138, r---while their Widest portions openiinto irecesses |14 and |16 on 'the valve |08. "The recess I14 1is connected, at all operating `positions of the -valve |08, through-apassage |1153 tora drained chamber (not shown) Similarly, thelrecess |15 isconnectedat all operating-positionspfthe `valveI' through a drain -port |80 and a conduit |82 to-a suitably drained chamber.

When the valve 4'|08 lis'in theposition lshown in Ithe drawing, all the ports leading l'to the oppositefends of-cylinder |62are closed'by the valve. If l'the valve moves upwardly from the position shown, then the hydraulic'pressure'uid may -fflow vthrough inlet port |68, recess |38, radial passage I4-8, `:passage l|50, A:drain port |52,

The upper end of valve |08 is keyed to a hub' |84 which carries a gear 06 driven by the engine through suitable driving mechanism, not shown. The valve |08 is thereby continuously rotated when the engine is running. Hence, when the valve |08 is moved upwardly from the vposition shown, the upper end of cylinder |62 is continu ously connected to the source of fluid pressure,

but the lower end of cylinder I 62 is connected to the drain only intermittently, as the tapered port formed by iiat |`|2 passes the ports |48 in the sleeve |46. As the distance of valve |08 from its neutral position increases, the width of the rport |12 which passes the port |48 on rotation of the valve, increases. Thus the proportion of the total time during which the pressure is being drained from the lower end of chamber |62 also increases. If the valve 08 is moved upwardly suiiiciently far so that land |36 clears the port |48completely, then the lower end of chamber |62 is continuously connected to the drain, and the piston |04 moves downward rapidly. Because of the intermittent action of the valve, the motion of the piston |04 takes place at a rate which depends upon the distance of valve |06 from the intermediate neutral position shown in the drawing.

The force due to the pressure acting upwardly on the bottom of valve |08 is a measure of the actual torque load on the engine. The force acting downwardly on the top of valve |08 is a measure of the desired torque load on the engine. When the actual torque is not equal to the desired torque, the valve |08 moves to cause operation ofY piston |04 to restore theactual torque to its desired value. The use of the flats |'|0and |12 and the rotation of the valve ensures that the rate of movement of the torque controlling piston |04 is varied in accordance with the amount of departure Vof the actual torque load from its desired value.

Provision is made for a by-pass connection between the ends of cylinder |62, toV permit manual operation of the torque control under emergency conditions. This by-pass includes a conduit |98 connecting the conduits |60 and |4. This conduit is controlled by a valve |90 operated by a solenoid |92. The electrical solenoid |92 may be energized by an electrically connected, battery |93, upon closing a switch |95. A spring |94 biases the valve |90 to a position wherein the by-pass is closed. vUpon manually closing switch |95, solenoid |92 is energized and overcomes spring |94, whereupon the valve |90V is opened, thereby permitting manual movement of Vthe pitch control by lever |91, mounted to rotate freely on shaft 99 and connected to shaft 92.

The rod ||2 is provided with a rounded lower end, and rides in asimilarly rounded crater in the top of hub |94, so as to provide for angular misalignment between the rod ||2 and hub |34. The lever mechanism ||4 includes a lever |95 and a lever |98 having opposed iiat surfaces which engage opposite portions of a bearing |22. The bearing |22 is carried at the end of a rod 200, which is moved laterally by a barometric control shown diagrammatically at |26 in Figure 2 and in greater detail in Figures 3, 4 and 5. TheV 6 rod ||2 ispivoted to the lever |96. The lever |98 is pivoted near its center at 202, `and the spring ||6 acts upwardly on its right end. The lower end of spring |6 engages a retainer 204 which is positioned bycam follower |28.

Cam I2 is fixed on a' hub 206, which is in turn keyed to the main control shaft 94 for rotation therewith. The connection of hub 206 to shaft 94 permits longitudinal movement of hub 206 along the shaft. The cam I8 has two cam surfaces 208 and 2|0, of different contours. These two cam surfaces lie side by side on the cam H8, so that the particular cam surface engaged by Sfollower |28 is determined by the lateral position of the cam. The left end of hub 206, as it appears in the drawing, is extended to form a piston 2|2 within a cylinder 2|4. The end of piston 2 l2 is provided with a flange, and a compression spring 2|6 retained between that ange and the cylinder 2|4 biases the piston to the left within the cylinder. Hydraulic fluid under pressure may be supplied to the cylinder 2 I4 through conduit 2|0, and is controlled by control valve mechanism |24.

The valve mechanism |24 includes a piston valve 220 operated by a bellows 224 located in a chamber 2255. The pressure of the water or other combustion regulating iiuid being supplied to the combustion chambers of the engine is communicated to chamber 226 through conduit 52. A spring 228 biases valve 220 to the position shown in the drawing, in which conduit 2|8 is in direct communication with a drain conduit 230. When water under pressure is supplied to chamber 226, bellows 224 and spring 228 are compressed, thereby moving valve 220 upwardly-so vas to connect conduit 2|0 to a conduit 232 which is supplied with hydraulic uid under pressure through conduits 234 and 236. When uid under rpressure is admitted through conduit 2|6 into cylinder 2|4, the piston 2|2 is moved to the right,rthereby moving the cam surface 208 under the follower |2i3, so that the force of spring ||6 is determined by the contour of cam surface 203, rather than by the contour of cam surface 2|0. When wateris not being supplied to the engine, the spring 228 moves valve 220 to the position shown in the drawing, and the conduit 2|8 isy connected to drain conduit 239. Spring 2|6 then moves the cam I8 to the position shown, wherein follower |26 rides on the cam surface 2|0f. The engine is capable of developing greater power and hence carrying a greater load when the combustion modifying fluid is being supplied-to the engine. Hence the contour of cam surface 203 is such that the force of spring H5 is increased when follower |28 is riding on that cam surface. Provision is made for reducing the torque load on the engine whenever the engine speed falls below the value for which the manual control lever 88 of Figure l is set. The manual control lever 23 rotates the shaft 95 which carries a cam 238 operating a follower 249 which controls the speed setting of the governor schematically in- @nested at sse. The governor is rotated. by the engine' driven shaft 95. `iii/'hen the engine speed falls below the value determined by the position of follower 240, the governor I3@ operates to lower a rod 242, which is connected through a strain relief spring 244 to another rod. 24S. The rod 246 extends upwardly through an opening in the lever |98 and is provided at its upper end with a ange 242.

the desired value, the flange 249 engages the When the rod 246 is movedA downward because the engine speed falls below' '17 fand whereby reducing th'e lspring force acting fdownwardly -onifvalve |08. ".This :operates the htorque .f'control y-s-yst'em Lto `rpartially unload fthe engine, #and :thereby z-iallows the speed @to recover its desiredwaluefmoref'quickly.

The control shaft .95 falso .carries -a tempera- 'Iiturereseti .cam i250 :and iai-fuel'. cam 252 Theiiuel :cam 252 .positions a"follower 25d which 'deter- 'miiresthe rate l kof fow 'of ffuel to 'fthe engine "by the mec'hanism'described'V inrconnectionwithillgrure'l. The `f`ffo'llower I=254` also carries an :arm'l2'5`6 z.which f'extends between a ".pair I of .pushrods 31253 Landiz.

` The'ipush :frods 'T5258 `:and 12160 are positioned :by ithe fluid "motor .device 1|32in .the temperature override controbmechanism. This :control mechf-anism operatesto 'reducelthe torque load onthe eng-ine and rto reducethe fuel flow wheneverthe tal `pipe temperature exceeds :1.a predetermined :value "Thelfuid motor device |322includesafpiston 52.621moving ina cylindervl. The lower end 4of fpist'on-ZGZ "is provided .with a :gear 21:2,1drivenizby the engine, so that the piston iscontinuously frotated. A spring 12114 biases lthe'piston 252 upfwardly against `the A.pressure inlV cylinder 2116; :A lateral surface ofipiston' 62'is provided with one or more slots' 2 1 l5i extending Vdownwardlyfromthe 'upper enddf'the piston. its 1the piston rotates,

thesefsiots zrs Vprovide intermittent communica tion between `fluid supply conduits 218 and '280 'and the cylinder '218. "The'conduit28` isfnorlm'allyflosed by-'v-a valve 'i92- contrll-ed' by thetem- "perature resetfcam`f2f5l). An outlet conduit 283 is provided for the A chamber i210, which `outlet lconduit isA controlled. by a vthermostatic -valve,"dia lgraminatically fin'dicated `at z21M, subject "to Ithe temperature vin thetail" pipe of-engine. The-iconstructi'on of the valve is 'such' thatitis 'normally closedrwhen the tailpipe temperature is in "the kallowablefrange of values. Thevalve'ZBdfopens whenever the tail g pipe temperature *exceeds the `desired value, "thereby reducing 'thempressure abovethe Ipiston'2i2 in the'cylinder l121|). The spring'ldthenmoves the piston upwardlyfcarrying with it'theApush rods'258'and-'250. Push rods 5260 V'acts Athrough a 'strain relief connection 2864 and a push rod 28B' on the'ri'ght'end of. a' lever 290. yA 'rod 12 S2 extends upwardly :from the Tleft end "of leverfS andthrough an aperture inthe lever B. The'rod 292 vis flanged atits upper end'as--indicate'd at :294. When thetemperature control movesthe rod V`288 upwardly,1the`lever' is carried'upwardly, so `thatit engagestherlan'ge 294 and moves rod2292 'and leverv |98'upwardly,"in a'torque decreasingv direction. Atthesametime, the upward movement/of push rod"258is transmitted throughl arm 255 to the'fu'el control mechanism to reduce the 'fuelsupply Both of these changes tend to reduce the engineitemperature.

In emergency conditions, itis desiredto increase the upper limit of power output by increasing the maximum permissible temperature. This'is done by the temperature reset cam250'. When the manual control'lever ismoved to its maximum rpower position, the cam 253 opens valve 282, thereby providing an additional supply of hydraulic iluid to the cylinder 2'|.,.and increasingthepressure therein. Undersuch condtions .the valve .284 which is subject tothe tail pipe temperature has toopen -Widerin order.to reduce the pressure `in cylinder Zm-.torapoint where the-push rod 25e-andtherelateditemperature controlmechanism are-operated `iso-reduce theltoiqu'e loadrand'the fuel'supply maure *s V`Figure illustrates in detail .zone form which the barometriccontrol |20 of-.Figure 2;.maytake.

-As .illustrated .in 'Figure '3, .this barometric econ- .trolfintzludesa.pair offopposed bellows 3`|l.and "3132. 'Ihe'interior of bellowsis. supplied with .huid at the .compressor inlet,pressure.by..means of aconduitwd. The two..bellowsareconnected by a .rod A306, on .which .is pivoted :a .lever $3.08. Theleft end of llever i338 is connectedby AYmeans of apin and .slot connectionto 4a.valv.e?.||l which .controls .the .supply-of .hydraulic ...fluid to a .fluid motor.. generallyindicated at...3 |.2. .Themotor-S-LZ includes a .piston .3 I @Lmoving .in .a .cylinder-MB.

.Thepiston '3M moves.a..rod 3|.8 whichisicon- 'bellows 302, vsothatits,inuenceon the-expansion and .contraction .of vthe bellows isbalanced out.

Thetwo bellows therefore.move-.the.rod.l3.06 up .and Adown in. accordance 4with .the diierence-.between ,the .compressor inlet pressure. insidebellows 'SUO .and the slibstantiallyfzero .pressureinside-:the

.evacuated bellows .302. The .compressor iinlet pressure used Vis .the..static .pressure, which isfa measureof .the barcmetric ,pressure, -whosechief v-ariation is in, accordance .withaltitudefso .far asaircraftare concerned.

.It-.may therefore .be .seenthat the twof bellows 393 and `3il2 move the rod 396 upandlown in accordance with variations.inatmospherimpressure, This motion is transmitted #through :lever 3138 to valve 3H), which .controlsthe .pistonlto cause a ollowingmovement-of `piston;rod.-3|8.

.For example, .if :the bellows 3 E..and-3.02 .move the rodSilfdownwardlyirom ythe.position shown inthe drawing, thenthe lever 368 pivotseabout itsrightend, movingvalve 3N: downwardly and admitting` hydraulic .fluid Vunder lpressure .-from conduit 320, past valve 3||ltand-throughconduit Y32.2.to vthecylinder 3|@ above .piston.31|.4. lfAt the Sametime, .the space incylinder 3 @below piston 3| 4 .-is connected through4 .a conduitr324 .andpast valve 3 Ei to a drain conduit326. The-.pistonM isaccordinglymoved downwardly by therdi-fferent pressures acting on it. This downward :movementof .piston 3|.4 rotates llever 338 .clockwise aboutitspivoton...the rod 30S. The valve .3|.0'is therebyraised to return to .itssneutralposition When Tthe .valve again reachesits neutral position,..the motionorpistonm stops. It-wilLbe readily v.understood ath-at, in .a :similar rmanner, upwardimovement of rodf361produces"a following4 upward. movement ofpiston 13 |114.

The-pistonrod' i8 carriesanarmf. `Pivoted ontlie'end'of arm- 328 is a link )33111, which-'extendsiupwardly 'frornthearm .32.8. -At'its upper end,:theilink'33| carries alroller 332 which rides onacarn 33t. The roller-332 is maintain'edin engagement with the-surface vof vcam "334 `by means of a 'bracket 336-pivoted on the 'link 330 and carryingja roller"338"which'engages'the oppositetsurface ofrcarn 334. Aspring 3'40`biases theibracket' and the link'33l3 apart-fand thereby maintains both vrollers `332 `ra'nliffin contact with the opposite `surfaces of'the cam. `Pivotally attached to the upper end of 'link33is'another link 290 which carries at its end a bearing |22 that moves between opposed facing surfaces of levers '|95 and |93. The link 20|), lbea-ring 122, andA levers 'L93 and i |98 yare the` same-parts-designated by vthose reference numerals in'Figure 2.V

is maintained in engagement with cam 346 by' means of a bracket 348, a roller 350, and av spring 352. which function in the same manner as the bracket 336, roller 338, and spring 340, just described. Pivotally attached to the upper end of link v342 is another link 352 which carries at its end a bearing 354 engaging surfaces on opposed levers 356 and 358.

The lateral position of bearing 354 is deteri mined by the pressures acting on bellows 300 and 302 and by the contour of cam 346. The bearing 354 and its related elements are parts of the fuel control system illustrated in Figure '7.

Figures 4 and 5 These two figures show alternative arrangements of bellows for operating the barometric control system of Figure 3. These two bellows systems differ from those of the prior art in that they add to the compressor inlet pressure the compressor discharge pressure so that the composite of these pressures, which is the same as J the compressor pressure differential, becomes the operating force lof the barometric control. The advantage of this arrangement, over using compressor inlet pressure alone, is that in the latter the overspeed governor has poor acceleration control and no temperature signal, whereas the Vformer getsgood acceleration control and full available horsepower at all airspeeds and air temperatures.

Figure 4 illustrates a casing 360, whose interior is subject to compressor inlet pressure by means of a conduit 362. Inside the housing 360 are mounted a pair of opposed bellows 364 and 366. Bellows 364 is evacuated, while the interior of bellows 366 is subjected to the compressor discharge pressure by means of a conduit 368. The two bellows 364 and 366 are connected by a rod 370, which carries a lever 306 corresponding in structure and function to the lever 308 of Figure 3. The bellows 364 has a larger area than the bellows 366. For the purpose of analyzing the operation of these two bellows, the bellows v364 may be considered as having one area equal to that of bellows 366 and a second area acting in the same direction as the rst'area, but unopposed by any areaof bellows 366. Considering the first area, it will be seen that the compressor impact pressure acts in anf'opposite direction on it to that in which it acts on bellows 366, so that its influence is balanced out. The bellows 366 and the first area of bellows 364, acting together, provide aV downward force on the rod 310 which varies with the absolute compressor discharge pressure. Considering the second area of bellows 364, it will be seen that it is subject to the compressor impact pressure acting downwardly. Therefore the rod 310 is moved downwardly by the sum of two forces, one of which varies with the absolute compressor discharge pressure and'one which varies with the absolute compressor inlet pressure. The compressor` discharge pressure is a measure of the rate of flow of combustion air to the engine. The compressor inlet pressure, on the other hand, is a measure of theair densityat thev altitude of flight.

. l0 In the apparatus of Figure 4, both these factors are considered in determining the torque output of the engine and the fuel ow to the engine.

Figure 5 illustrates an arrangement of bellows equivalent in effect to the arrangement shown in Figure 4. Figure 5 shows a casing 3!0 containing a lower bellows 372, which is evacuated, and a pair of concentric upper bellows 334 and 316. The inner bellows 316 is supplied with fluid at the compressor discharge pressure through a conduit 318. The outer bellows 34 is supplied with fluid at the compressor inlet pressure through a conduit-336. The pressure within the casing 336 outside the bellows may be any desired pressure. The three bellows are connected by a rod 382.

It is believed to be obvious without any-elaborate analysis that vthe bellows system of Figure 5 produces a net force acting downward on rod 382, which is the sum ci one force varying with the compressor inlet pressure and a second force varying with the compressor discharge pressure.

Figure 6 This figure illustrates a valve structure which may be used in place of the valve mechanism |06 of Figure 2. Like the valve mechanism |06, the valve arrangement shown in Figure 6 will produce a rate of movement of the motor controlled by it, which varies in accordance with the amount of unbalance between the controlling forces acting on opposite ends of the valve. In the structure of Figure 6, this result is accomplished by the use of a heavy cantilever spring which biases the valve toward its neutral position in such a manner that under normal operating conditions,

the valve will not depart from its neutral position by more than a few thousandths of an inch. In this way, a much simpler valve structure may be used than in Figure 2, with a very similar result.

Referring to Figure 6, there is shown a piston valve 400 having a pair of spaced lands 402 and 404. These lands cover ports leading to the opposite ends of a fluid motor when the valve is in its neutral position, as shown in the drawing.

The central recess between the lands is connected to a source of fluid pressure (not shown) and the recesses on the other sides of the two lands are connected to suitable drains (not shown). The connections between the valve, the pressure source, the drains, and the fluid motor, are substantially the same asV those of valve mechanism |06 of Figure 2. The upper endA of thervalve carries a gear 406 by which itis continuously rotated to prevent sticking. The lower end of the valve is exposed to the torque measuring uid pressure in a chamber 4|0, which corresponds to the chamber l0 of Figure 2. The downward controlling force acting on the Valve is transmitted through a bearing pin 4|2 in the end of a lever 4|4. The pin 4I2 corresponds to the rod H2 of Figure 2. Between the lower end of pin 4|2 and an abutment 4|6 on the upper end of the valve 460 lies the end of a leaf spring 4|8. The right end of the leaf spring 4|8 is attached to a xed support 420. A central portion of the leaf spring v4|l-l is attached to an adjustable support generally including a pin 422 which extends through a bushing 424 in the casting 426. The upper end of pin 422 is flanged to engage the upper surface of leaf spring 4| 8. The

itfmay be, rotated by a screw driver or other suitableftool. to' adjust the vertical positionfpfthe centralportion of leafrspring 418, thereby, ad'- justiner4 the neutral position of valve 40j'A1ock. nut"4 3[ land aV cap 432 are provided on the lowerV end fpin 422 to hold it in any desredajusted Figure 7 7:; shows. the, fuel. owcontrol system i Whll; together with: theV apparatus. shown Fig uresf2 and Secolmletes the .controlapparatus schematically indicated at 54 in Figure 1. 'Ihisv fuel.;` control apparatus. regulates.. the` hydraulic pressure transmitted .f through vconduit. 56 .of Fig--y ure, l to determine ther delivery oiftheipressure responsivevariable. delivery fuel pump 2.6..; This.. variapleiuel ,controlling pressure. is established in @semence-With. (l) the..enene speeds (2).. the-- operation of the barometriccontrol, and (3) the position of the manually operated control lever 2r Y A. .j

There, .isshownimligure .7.a valve 4401 which regulates. the f pressure .acting onA the under sideof-apist'on 442;. whichY pressure iis transmitted. toi conduiti 55; The..valve..44llmoves in ai loorein` ,m a casting :44.4. Wheninthe .position shown in thedravving, the. ,valve 4401..traps the fluid inltheV chamberrunder piston 442'.' When the=valver44 is movedzzdownward-,from thatpositio-n, itadmits iiuidifron'iV a conduit. 446;througha conduit,448 to the.;chamber..451).3 WhenY thervalve'. 448 is' moved@ upwardxfroml the position. shown in thedrawing; itgpermits-ithe. uidin `clzxamloer. 456)` to drain Athrong-nine. recess in, .theivalvecut-l through thenpper A.endoi ,the valve.. bore.

A.- rod i454 fhayingfits. lower .endvroundedrests 4 a spherical seat in the upper surface of pistoni 442-` The; upperenduof .valve .440. carries .a lever 452 whose left-@endis connected byna pinand slotconneotion;to-the.rod 454.. Theupperendof rodv disconnected-to, a...lelver:.358.o .a variable. ratio 45 lever mechanism B, parts of .-,wh-chwereishown and...descrbedinconnectiontwith Figure S3.. 'I-he leverimechanism; .variesthe force appliedi-byla sp.1.ing.-45;8,l to. .the ,rod..4541in.,accordancefvvith theoperatiori .of `ithe.zbarometriccontrol. f

Theright end ,of lever 452 .hasa screw1 460ad just/ably; attached ftheretm The lowermendot screvii..'46lliengaefesL or may engfage-ranliarrnf256- carriedlbylaifollower 254;;Which zcooperates v'vith thef-uekcam V252i' The extreme right end of'1lever1i55 452.=;rdes I on an Y. arm.;462i operated; by vgolver-nor l 3mi .Y

When the engine. speed. fallsbelow. Athe desired valuegthe governor lowers armVABZtthereby-'turhing. ,leveli- 4521fr` clockwise, `about i its left xend; and lowering valve `4.4 IJL This'admits fluid :under pressure. through conduit. 448 :into .chamber 450, thereby; hlcreasing thegfuel. :flow toLLthe engi-ne and f movirf igpiston,.442 lupwardly to restore'valve44i] i to itsneutral position.;

The .Cam...25?... and. its relatedelements afiects the-.fuel,flowvonly during conditions of. accelera-f ton,pvhen thllginepeed is considerablyebelow the@ n.eteds deiedbriheeovernor. Under: sucfh voedtiellstheermf?55 stops thed0.rinviareY .70 miniem? at, .-SC1"W .450. anthebrylimts the i ratedf selaiee. Offihs resins.

'iterate of'iwfueliehesnsirie isfmodb.

fledabyth. er-tic CQnifOl acting. through: beingjgi rm. .messageimeeeseaithet the ,75

i me

` liqui pending application No. 7zo.3s,gn1 ,fr 19;: 19.47, previously referredto. Therearealsofshown inf that application.tliestructural'details .'o

0f.' th parts 0f myn-0911131.01 .Whht shown im. 4 th@ PYCSBIT applicationlr'onl'ylA da matically; i 4 Y hetermsand expessio .,-usedhereinare.em.f

P19-Yee, fv '1511115954252 bfleSlxiilti i; limitation, and I have no intention, such."'terrns`A and, expressionIs',YL oil. exludin a y, eqivalentspf..thefeatllefhown @iid-d. ib. u or'portions thereof, butreconizthatvar lis, modifications, arepossiblewithin the As'zoifie invention claimed;

'ijelaim asmyinventon;

21 Cee-tjmlifapprawe fe aeiiriternelombus: tion enginq'and.- af variable torque:loadl fdriven. thereby, comprising A means.; for regulating, thel torseeo Said load, Couriel meenam v@Irinathe;A torque .val-111e. .te 'be memainsdffbsSaieirsillatv.. ine. mee/.11s means f fer..- Supplyina a. Combustioni ing-th I'rel tionsh mssiiffvins ..flvidfteSaidfensine. and means elise.:

tiisfupoaoneraiiszn ensei@ flu-i@ Supplyiesmseea t0 mesgfy the reletieeship `betvveri.iili @nir-01.. means and said torque regulating n'ieanse,V

3-. Ceetml apparatuses laim, i 2.; in .which .regulaistmsens includes aoriirol. :pensive fwtheposition ,0f saisi; varying.:sai/dieren@ and gineansre -Y SDOlS'L.. efiheiteliqusgl'faed.Yf0r-..positier1ine.,Saidi Elment. siii-@Htmlmserisincludes a manually. movable lever, a5L cani lmfi/ fby said4 lever, and

@arresting Seid .Cem endsaidtcon: that movement 0f,aid...1ever.varies si onto,

i e nlldmeelifqmblling :S2451 .Cam laterally Cerise-.1: ergeren-1s asinicleim-z, inl-which bustiony mgdiiyingfluid is v`a liquid,; said;y u rafm ans/,deli YSayid..liquid .Ulldptess Surse eedeseidsntodiyi s means inclus-ies .eX-)- Dalflillffbltlow.; Sllbleet iQ-:said .liquid -pressure-. ql2 f in ClaimZi, ineludine;

y spegeclloi` said enginefor. .P1.0f-.fuel..theneto to. freeillate` ,i e at oiseleeiedevalueiandmeansmove. Witlriseidconir-o1; means.fOr-f` ,Vetrine @alii .-Seleetedzsped valueV 6., HControlapparatus.for,ani .internal combustionferienescQIIm-rising mme for; :regulating the.. t o f said-engine,;. me;ans `for varying, v saidregulating meansincludinga. n movapledeven ancam rnoved :loysaid'.V lever n .fqlleweremeans .Connecting i said faam nd'sai Setting..ivarrinemeanslsaici cam. having. a parfgpagrlllel cam surfaces andbeingmovable laterally; to; Present :selectively .said surfaces...to Sadf .lPWel-meane means. forsupplyingacorn-y i 13 bustion modifying substance to said engine, and means effective upon operation of said substance supplying means to move said cam laterally.

7. Control Iapparatus for an internal combustion engine and a variable torque load driven thereby, comprising means for varying the torque of said load, motor means for driving said torque varying means, control means for said motor means including a control element having a neutral position and effective upon opposite movements from said position to cause operation of said motor means in opposite directions, means for applying to said element a force acting in a torque decreasing direction and varying in accordance with the output torque of said engine, means for applying to said element an opposing force acting in a torque increasing direction, said last-named means comprising a pair of levers extending generally parallel to one another and each having a surface facing a similar surface on the other, a bearing located between and contacting both of said surfaces, means responsive to the rate of combustion yair flow to said engine for moving said bearing along said surfaces to vary the mechanical advantage Of said levers, a connection between one of said levers andsaid control element, spring means acting on the other of said levers in a torque increasing direction, manually operable means for varying the force of said spring means, and means responsive to the speed of said engine for moving said other lever in a torque decreasing direction when said speed exceeds a predetermined value.

8. Control apparatus as in claim 7, including means responsive to a temperature in said engine for moving said other lever in a torque decreasing direction when said temperature exceeds predetermined value.

9. Control apparatus as in claim 2, including means responsive to the speed of said engine for controlling the supply of fuel thereto to regulate said speed at a selected value, means movable concurrently with said speed-responsive control means for varying said selected speed value, said movable means being effective to yincrease said selected value from minimum to maximum upon movement over substantially one-half of its total range of travel, means responsive to a temperature in said engine for reducing the fuel supply when said temperature exceeds a predetermined value, and means movable concurrently with said control means and effective at a xed point in the travel of said control means after said speed value varying means has reached its maximum speed position to increase said predetermined temperature value.

10. Control apparatus for a power plant including an internal combustion engine having a fuel supply thereto, a variable torque load driven thereby, and a compressor for supplying combuston air to said engine, said control apparatus comprising means subject to the pressure at the compressor inlet and the pressure at the compressor outlet and responsive to the composite, net force of said pressures, and means including said pressure responsive means for varying the torque load.

11. Control apparatus for a power plant including an internal combustion engine having a fuel supply thereto, a variable torque load driven thereby, and a compressor for supplying combustion air thereto, said control apparatus comprising: means subject to the pressure at the compressor inlet and the pressure at the compressor outlet and responsive to the differential of said pressures; means including said pressures differential responsive means for varying the torque load; and means operated by said pressure differentia1 responsive means for varying the supply of fuel to said engine.

LEIGHTON LEE II.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,052,588 Janicki Feb. 11, 1913 1,346,509 Olhovsky July 13, 1920 1,908,396 Albright May 9, 1933 1,959,795 Lysholm May 22, 1934 2,124,274 Nichols July 19, 1938 2,193,114 Seippel Mar. 12, 1940 2,283,541 Dodson May 19, 1942 2,304,784 Donaldson Dec. 15, 1942 2,306,953 Jung Dec. 29, 1942 2,322,303 Martin June 22, 1943 2,336,232 Doran Dec. 7, 1943 2,407,317 Mennesson Sept. 10, 1946 2,422,808 Stokes June 24, 1947 2,424,559 Drake July 29, 1947 2,426,007 Forsyth Aug. 19, 1947 2,429,189 Maddox Oct. 14, 1947 2,447,263 Mock Aug. 17, 1948 2,457,595 Orr Dec. 28, 1948 2,555,445 Hooker et al. June 5, 1951 2,618,927 Chandler Nov. 25, 1952 FOREIGN PATENTS Number Country Date 923,513 France Feb. 17, 1947 549,105

Great Britain Nov. 6, 1942 

